| ??? 02/16/05 10:43 Read: times |
#87637 - Thanks Responding to: ???'s previous message |
Thanks for all the responses. As far as I can tell the problem was a combination of not having VPP/~EA connected to VCC and the ground bounce from the 74F chip (which wouldn't have occured to me if I was here till this time next year, thanks again).
The only reason I was using a F chip instead of a LS chip is for another part of the design I need the inverter to sink more current than the LS chip can accommodate (the speed is not a factor). As far as I know a S or an AL chip will do me for this also and I was just wondering if there is likely to be any problem with ground bounce with these. (And before anybody says to read the datasheet I already have, but I didn't pick up on this problem when I read the datasheet for the F chip so ...) |
| Topic | Author | Date |
| Problem getting 8051 chip to work | 01/01/70 00:00 | |
| tie ~EA pin to Vcc | 01/01/70 00:00 | |
| tie Vpp/~EA pin to Vcc | 01/01/70 00:00 | |
| to connect or not? | 01/01/70 00:00 | |
| conbnect | 01/01/70 00:00 | |
| If it helps.... | 01/01/70 00:00 | |
| Reset Capacitor | 01/01/70 00:00 | |
| connect | 01/01/70 00:00 | |
| T89C51RD2 | 01/01/70 00:00 | |
| This device is ISP | 01/01/70 00:00 | |
| VCC and GND? | 01/01/70 00:00 | |
| I think you do not load | 01/01/70 00:00 | |
| Series resistor for LED? | 01/01/70 00:00 | |
| 74F14 | 01/01/70 00:00 | |
| give me +1 too | 01/01/70 00:00 | |
| done | 01/01/70 00:00 | |
| Sorry | 01/01/70 00:00 | |
| LED Polarity | 01/01/70 00:00 | |
| Does not seem to be the cause | 01/01/70 00:00 | |
| Ouch! | 01/01/70 00:00 | |
| FAST-TTL and breadboarded design | 01/01/70 00:00 | |
| Ground bounce | 01/01/70 00:00 | |
| Bad news 74F =( | 01/01/70 00:00 | |
| HCT? | 01/01/70 00:00 | |
| LS, HCT and maybe AHCT | 01/01/70 00:00 | |
| Got it | 01/01/70 00:00 | |
| wire wrap and breadboards | 01/01/70 00:00 | |
| I use protoboard | 01/01/70 00:00 | |
| the problem with that is | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| Why do you want to use 74F chips? | 01/01/70 00:00 | |
well... | 01/01/70 00:00 | |
| maybe you are still in ISP mode? | 01/01/70 00:00 | |
| 1st things 1st please | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| bounce on non PCB | 01/01/70 00:00 | |
| Analytical thinking | 01/01/70 00:00 |